body {
      font-family: 'Segoe UI', sans-serif;
      background-color: #f8f9fa;
    }
    .sidebar {
      height: 100vh;
      background-color: #0d6efd;
      color: #fff;
    }
    .sidebar a {
      color: #fff;
      text-decoration: none;
      display: block;
      padding: 12px 20px;
    }
    .sidebar a:hover {
      background-color: #0b5ed7;
    }
    .card-icon {
      font-size: 2rem;
    }

    body.dark-mode {
      background-color: #121212;
      color: #ffffff;
    }
    .dark-mode .card, .dark-mode .navbar, .dark-mode .toast {
      background-color: #1e1e1e;
      color: #ffffff;
    }
    .toast-container {
      position: fixed;
      top: 1rem;
      right: 1rem;
      z-index: 9999;
    }